The present invention relates to a master batch of an organic peroxide, a thermoplastic resin composition obtained by using the master batch, and methods of manufacturing the master batch and the composition.
A conventional master batch containing a crosslinking agent causes a problem of forming lumps in molding procedures. Here, xe2x80x9clumpsxe2x80x9d are gels caused by local excess crosslinking due to an unevenly dispersed crosslinking agent or crosslinking aid, and polymerized crosslinking aid itself. In injection molding, even if lumps are formed, they appear rarely on the surfaces of molded articles, so that the articles can be placed on the market. However, in extrusion molding, the lumps appear on the surfaces of molded articles to damage appearance of the articles.
It is known that a crosslinking agent and a crosslinking aid are added simultaneously and kneaded in producing a resin composition. Since it is difficult to uniformly disperse the crosslinking agent and the crosslinking aid in the composition, there occur such problems as formation of gels and bad dispersion.
Generally, the crosslinking agent and the crosslinking aid are used in such a manner that they are absorbed in a resin or an inorganic substance. In that case, an absorption process is required, which makes the process more complex and costly. Particularly where they are absorbed in an inorganic substance, a problem arises that a specific gravity of a resin composition ultimately obtained is greater than where they are absorbed in a resin.
In addition, there is a problem in storing a resin composition comprising a crosslinking agent because an organic peroxide as the crosslinking agent decomposes. Thus, a manner of storing the composition is restricted.
The present invention provides a master batch of an organic peroxide in which the organic peroxide is so uniformly dispersed in a thermoplastic resin that crosslinking and/or decomposition occur uniformly, a method of preparing the same, a thermoplastic resin composition obtained using the master batch and a method of preparing the same.
Thus, the present invention is
(1) a thermoplastic resin composition comprising
(a) 100 parts by weight of a block copolymer comprising at least two polymeric blocks A composed mainly of a vinyl aromatic compound and at least one polymeric block B composed mainly of a conjugated diene compound, or a hydrogenated block copolymer thereof,
(d) 5 to 50 parts by weight of an organic peroxide, and
(e) 10 to 80 parts by weight of one or more substances selected from the group consisting of multifunctional vinyl compounds and multifunctional (meth)acrylate compounds.
Further, the present invention is
(2) the thermoplastic resin composition according to (1) above, wherein the composition further comprises
(b) 15 to 45 parts by weight of a liquid polybutadiene, or
(c) 15 to 45 parts by weight of a branched saturated hydrocarbon having 4 to 155 carbon atoms, or both (b) and (c), and
(f) 0 to 5 parts by weight of a lubricant.
In the above resin compositions, i.e., master batches of organic peroxide, component (d) is uniformly dispersed because of the presence of component (e), preferably both component (e) and component (c). When melt-kneading the master batch with the thermoplastic resin composition which comprises component (j), or components (a), (g), (h) and (i) as will be described below crosslinking and/or decomposition reaction occurs uniformly in the thermoplastic resin.
Uniform dispersion of component (d) in the master batch can be attained by kneading at a temperature of 100xc2x0 C. or lower, so that a crosslinking reaction is prohibited in kneading procedure.
In melt-kneading procedure for the thermoplastic resin composition using the master batch, component (c) slows down crosslinking and/or decomposition reaction to allow component (d) to be dispersed uniformly and to cause crosslinking or decomposition reaction uniformly in a controlled speed. For this reason, it is believed that the lumps are not formed in a molded article. The amount of component (c) may depend on its ability to slow down the reaction.
Because an organic peroxide is not made absorbed in a resin or inorganic substance, the present master batch is easy to handle and can be stored in stable state.
Another aspect of the present invention is
(3) a method of preparing a thermoplastic resin composition comprising a first step for preparing thermoplastic resin composition (I) by kneading
(a) 100 parts by weight of a block copolymer comprising at least two polymeric blocks A composed mainly of a vinyl aromatic compound and at least one polymeric block B composed mainly of a conjugated diene compound, or a hydrogenated block copolymer thereof,
(b) 15 to 45 parts by weight of a liquid polybutadiene,
(c) 15 to 45 parts by weight of a branched saturated hydrocarbon having 4 to 155 carbon atoms,
(d) 5 to 50 parts by weight of an organic peroxide, and
(e) 10 to 80 parts by weight of one or more substances selected from the group consisting of multifunctional vinyl compounds and multifunctional (meth)acrylate compounds, and
(f) 0 to 5 parts by weight of a lubricant at a temperature of 100xc2x0 C. or lower, and a second step of melt-kneading 3 to 50 parts by weight of said thermoplastic resin composition (I) with
(j) 100 parts by weight of one or more thermoplastic resins selected from the group consisting of styrene-butadiene-styrene copolymers, styrene-isoprene-styrene copolymers, styrene-(ethylene/butene)-styrene copolymers, styrene-(ethylene/propylene)-styrene copolymers, styrene-(ethylene/ethylene/propylene)-styrene copolymers, styrene-butadiene rubbers, butadiene rubbers, polybutadienes, isoprene rubbers, acrylonitrile-butadiene rubbers, chloroprene rubbers, ethylene-propylene rubbers, ethylene-propylene-diene terpolymers, butyl rubbers, acrylic rubbers, polyolefin resins, thermoplastic polyester elastomers, thermoplastic polyurethane elastomers and thermoplastic amide elastomers.
Also the present invention is a method of preparing a thermoplastic resin composition comprising a first step for preparing thermoplastic resin composition (I) by kneading
(a) 100 parts by weight of a block copolymer comprising at least two polymeric blocks A composed mainly of a vinyl aromatic compound and at least one polymeric block B composed mainly of a conjugated diene compound, or a hydrogenated block copolymer thereof,
(b) 15 to 45 parts by weight of a liquid polybutadiene,
(c) 15 to 45 parts by weight of a branched saturated hydrocarbon having 4 to 155 carbon atoms,
(d) 5 to 50 parts by weight of an organic peroxide, and
(e) 10 to 80 parts by weight of one or more substances selected from the group consisting of multifunctional vinyl compounds and multifunctional (meth)acrylate compounds, and
(f) 0 to 5 parts by weight of a lubricant at a temperature of 100xc2x0 C. or lower, and a second step of melt-kneading 3 to 50 parts by weight of said thermoplastic resin composition (I) with
(a) 100 parts by weight of a block copolymer comprising at least two polymeric blocks A composed mainly of a vinyl aromatic compound and at least one polymeric block B composed mainly of a conjugated diene compound, or a hydrogenated block copolymer thereof,
(g) 10 to 1,000 parts by weight of a non-aromatic softening agent for rubbers,
(h) 0 to 150 parts by weight of a peroxide-decomposing olefinic resin, or a peroxide-decomposing olefinic copolymer rubber, and
(i) 0 to 150 parts by weight of a peroxide-crosslinking olefinic resin, or a peroxide-crosslinking olefinic copolymer rubber.
The preferred embodiments of the invention are as follows:
(5) a thermoplastic resin composition comprising 3 to 50 parts by weight of the thermoplastic resin composition according to (1) or (2) above, and
(j) 100 parts by weight of one or more thermoplastic resins selected from the group consisting of styrene-butadiene-styrene copolymers, styrene-isoprene-styrene copolymers, styrene-(ethylene/butene)-styrene copolymers, styrene-(ethylene/propylene)-styrene copolymers, styrene-(ethylene/ethylene/propylene)-styrene copolymers, styrene-butadiene rubbers, butadiene rubbers, polybutadienes, isoprene rubbers, acrylonitrile-butadiene rubbers, chloroprene rubbers, ethylene-propylene rubbers, ethylene-propylene-diene terpolymers, butyl rubbers, acrylic rubbers, polyolefin resins, thermoplastic polyester elastomers, thermoplastic polyurethane elastomers and thermoplastic amide elastomers, and
(6) a thermoplastic resin composition comprising 3 to 50 parts by weight of the thermoplastic resin composition according to according to (1) or (2) above, and
(a) 100 parts by weight of a block copolymer comprising at least two polymeric blocks A composed mainly of a vinyl aromatic compound and at least one polymeric block B composed mainly of a conjugated diene compound, or a hydrogenated block copolymer thereof,
(g) 10 to 1,000 parts by weight of a non-aromatic softening agent for rubbers,
(h) 0 to 150 parts by weight of a peroxide-decomposing olefin resin, or a peroxide-decomposing olefinic copolymer rubber, and
(i) 0 to 150 parts by weight of a peroxide-crosslinking olefin resin, or a peroxide-crosslinking olefinic copolymer rubber.